Equivalent to "pwnd," but much more l33t. The term "pwnd" was originally a typo (p is next to o on the keyboard); "ywnd" is a repetition of that same typo, but using a Dvorak keyboard (y is next to p in you are typing with a Dvorak keyboard layout). Dvorak is much more l33t than Qwerty -- hence "ywnd" is more l33t than "pwnd."
A: DUUUDDEE you just got ywnd noob
B: ywnd?? you mean pwnd?
A: lol dumb qwerty noob